Active Earth Observing Satellites (EOS) (as of 8/31/2015)

• Total number of operating satellites: 1,305
• Total Earth Observing Satellites (EOS): 333
  • United States: 34%
  • China: 21%
    
  • Japan 6.3%

From the Union of Concerned Scientists Satellite Database and Pixalytics Blog

Debris & Satellites in low Earth orbit

Image courtesy of European Space Agency

NASA’s Earth Observing System

Passive Remote Sensing

Electromagnetic Radiation

EarthData.nasa.gov

Datasets, news, articles, information

EarthData.nasa.gov

Datasets, news, articles, information

Moderate Resolution Imaging Spectroradiometer (MODIS)

2 Satellites Terra launched in 1999, Aqua in 2002.

Technical Details: swath

Viewing swath width of 2,330 km

Technical Details: spatial coverage

Covers Earth every one to two days

Technical Details: spectral coverage

36 spectral bands between 0.405 and 14.385 µm

Technical Details: spatial resolution

3 spatial resolutions – 250m, 500m, and 1,000m

MODIS Data Processing

• Tracking and Data Relay Satellite System in White Sands, New Mexico
• EOS Data and Operations System @ Goddard Space Flight Center in Greenbelt, MD
• MODIS Adaptive Processing System (MODAPS)
• 3 DAACs for distribution

MODIS products (a subset…)

Atmosphere

• Aerosol & Clouds
• Total Precipitable Water

Cryosphere Products

• Snow Cover
• Sea Ice and Ice Surface Temperature

Ocean Products

• Sea Surface Temperature
• Sub-surface Chlorophyll-a Concentration
• Particulate Carbon
• Photosynthetically Available Radiation

Land Products

• Surface Reflectance
• Land Surface Temperature and Emissivity
• Land Cover Products
• Vegetation Index Products (NDVI and EVI)
• Thermal Anomalies - Active Fires
• Photosynthetically Active Radiation (FPAR) / Leaf Area Index (LAI)
• Evapotranspiration
• Primary Productivity
• Vegetation Continuous Fields
• Water Mask
• Burned Area Product

Example product workflow

MODIS Products used to generate vegetation indices. From the MOD13 Algorithm Theoretical Basis Document.

Data formats

Most NASA EOS data distributed as HDF files, which are very similar to netCDF.

NetCDF / HDF

Collection-Level Naming Conventsions

MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid V005

• MODIS/Terra - Instrument/Sensor
• Surface Reflectance - Geophysical Parameter
• 8-Day - Temporal Resolution
• L3 - Processing Level
• Global - Global or Swath
• 500m - Spatial Resolution
• SIN Grid - Gridded or Not
• V005 - Collection Version

MODIS Gridding system

Filename Conventions

MOD09A1.A2006001.h08v05.005.2006012234657.hdf

• MOD09A1 - Product Short Name
• .A2006001 - Julian Date of Acquisition (A-YYYYDDD)
• .h08v05 - Tile Identifier (horizontalXXverticalYY)
• .005 - Collection Version
• .2006012234567 - Julian Date of Production (YYYYDDDHHMMSS)
• .hdf - Data Format (HDF-EOS)

MODIS Temporal Resolution

• Daily
• 8-Day
• 16-Day
• Monthly
• Quarterly
• Yearly

MODIS Spatial Resolution

• Bands 1–2 250-meter
• Bands 3–7 500-meter
• Bands 8–36 1000-meter

Distributed Active Archive Centers (DAACs)

• **Level 1 data:** geolocation, cloud mask, and atmosphere products ladsweb.nascom.nasa.gov
• Land products: lpdaac.usgs.gov
• Cryosphere (snow/ice) products: nsidc.org/daac/modis
• Ocean color and sea surface temperature: oceancolor.gsfc.nasa.gov

Accessing data

The Land Processes Distributed Active Archive Center has a nice “Data Discovery” Tool:

MODIS Products Table

Lists all available MODIS land products

Annual Land Cover Type Description

Detailed layer information

Data access links

Downloading: http/ftp access

or the LP DAAC2Disk Download Manager which builds a download script.

MODIS Reprojection Tool

Available at lpdaac.usgs.gov/tools/modis_reprojection_tool.

MODIS Reprojection Tool: Subset & Reproject

MCD12Q1.A2012001.h12v04.051.2014288200441.hdf

MODIS Web Services

daacmodis.ornl.gov/cgi-bin/MODIS/GLBVIZ_1_Glb/modis_subset_order_global_col5.pl

• Provide access to regional subsets (<100x100km)
• Merge across tiles
• Download full time series

MODIS Subset: Spatial

MODIS Subset: Variables

MODIS Subset: Temporal

Submit email and wait for results…

MODIS Subset: Results & Download

MODIS Subsets: API

Subsets of MODIS Land Products through Simple Object Access Protocol (SOAP).

MODISTools R package.

Presentation Credits

• Images: NASA
• Some contents from Steve Ackerman stevea@ssec.wisc.edu, Cooperative Institute for Meteorological Satellite Studies, University of Wisconsin-Madison